In theory, “The Fall Guy” may be former stuntman David Leitch’s loving tribute to stunt professionals, but in practice, it’s a demonstration of the importance of movie star charisma. Loosely based on the 1980s TV show that starred Lee Majors as a stunt man moonlighting as a bounty hunter, “The Fall Guy” orbits around one person with a planetary-sized screen presence, Ryan Gosling. Hair streaked…